Do you mean load bearing?

If you're repainting anyway, it's not rocket science to have a new header put in. It's hard to separate that part of the job, but the hole and drywall wasn't more than $1000.

If you mean like earthquakes and hurricanes, you'll have to strip more drywall and add blocking and straps. That's a bit more expensive, but not really if you have to go back to studs anyway.

Milly thanks for responding!

No it's not about load bearing, which is much more straight forward. Shear walls are for earthquakes and winds (which can also be hurricanes of course). The few articles I could find often made reference to how little contractors and sometimes architects understand shear walls and their importance. Now I have more questions than answers.

We weren't going to have to pull out all the drywall down to the studs. From the little I could get on the web, it sounds like we will need a structural engineer's plan, then whatever is recommended. Doesn't sound like a lot in materials, but could be a lot in labor. I have no idea what all this would entail and cost. I also don't know how large of a window we can have since the shear wall has to be brought up to the proper strengh again. The house is 20 years old if that makes any difference. I already posted about this on the remodeling forum and got no replies. I may just have to pay a structural engineer just to give me an answer and then I can decide how to proceed or not.

A shear wall provides bracing against lateral forces that would twist the framing. Full sheet sheathing is usually one component of that engineering. Placing holes in that wall is not complicated, depending on where you want to place them. Corners are more fraught with issues than along the middle. Cables and turnbuckles inserted into the framing to create diagonal bracing would need to be designed by a structural engineer. Obviously, you would need access to the framing for that to happen. Removing and replacing drywall is cheap. Installing the bracing isn't expensive. Windows aren't cheap, but overall, in most situations, if you are already doing drywall repair in the project, you can likely add this for a couple of thousand over the other ancillary costs.

I didn't have shear walls, but when I added a window in bathroom and altered a window in the kitchen, the city required them. This was after I had signed the contract with my GC. So a bedroom ended up being gutted down to the studs and bracing added. I asked GC how much additional cost, and he did not charge me extra. It was done and inspected during a week I was out of town. GC did say the permit fees for my remodel were the highest he'd seen, partly due to the shear walls. And there was extra cost for the engineer to sign off on the drawings.

Not saying that your GC should do it for free, but I doubt it would be cost prohibitive relative to adding the window

Joseph - in my town, adding any new opening to a wall, be it load bearing or not, requires not only a permit, but a struct. engineer. If the wall is not load bearing, the engineer's signature is needed, stating that work can progress without drawings. Otherwise, struct. engineers drawings with calculations are required.

Best to get a permit with all it entails than incurring the officials wrath and accompanying fines, as almost daily, I see Inspector's vehicles cruising the neighborhood looking out for contractor trucks in driveways.

This has been very helpful!

My windows will be in the middle of the wall so that sounds good. We'd like to take out a post in the dining room area too, so we can get options for removing that while we're at it.

Hopefully if others need/want to find out more about shear walls, they will have a resource.

Joseph - in my town, adding any new
opening to a wall, be it load bearing or not, requires not only a
permit, but a struct. engineer. If the wall is not load bearing, the
engineer's signature is needed, stating that work can progress without
drawings. Otherwise, struct. engineers drawings with calculations are
required.

Best to get a permit with all it entails than incurring the officials
wrath and accompanying fines, as almost daily, I see Inspector's
vehicles cruising the neighborhood looking out for contractor trucks in
driveways.

This is also true for my city. Every time we changed windows or walls, we got the OK of a structural engineer. Additionally, depending on how much window surface area you have in your house, you maybe at the limit of the window area.

If you have an earthquake insurance, I would not do anything that may
void the insurance. Earthquake insurances are difficult and expensive to
get.